• 한국재료학회지
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• 제15권10호
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• pp.678-682
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• 2005

We studied the possibility of $Zn_4O(Ac)_2(OH)$ formation as a precursor for ZnO nano particles in sol-gel method. Four different additives such as tetra methyl ammonium hydroxide, mono ethanol amine (MEA), LiOH, and $H_2O$ were used for zinc acetate dissolved in 2-methoxy ethanol. ZnO particles of 5-6 nm in size were observed. Existence of $Zn_4O(Ac)_6$ was not verified. $Zn_4O(Ac)_2(OH)$ molecules were observed and they were believed to be the precursors of ZnO. A peak at 275nm in UV-Vis analysis was observed In the case of MEA and $H_2O$ but no ZnO particles were detected in transmission electron microscopy.

• 대한치과교정학회지
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• 제5권1호
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• pp.21-24
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• 1975

The purpose of this study was to investigate the effect of sinc phosphate cement on the enamel surface of extracted teeth. The tooth was placed in a test tube, which was subjected to 5ml of 0.2M acetate buffer at pH 4 by 'window technique.' The calcium content of the acetate buffer was determined by the Perkin-Elmer Model 303 Atomic Absorption Spectrophotometer. The obtained results were summarized in the following. 1. The solubility of enamel is $0.92mg/cm^2$. ml in control group. 2. The solubility of enamel is increased by treating these with zinc phosphate cements. 3. The solubility of enamel is $0.69mg/cm^2$. ml by treating with Lee Smith cement. 4. The solubility of enamel is $0.30mg/cm^2$. ml by treating with G-C's cement.

• 약학회지
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• 제33권4호
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• pp.237-240
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• 1989

A new synthetic method for tiaprofenic acid, which is a potent anti-inflammatory agent, was described. Friedel-Crafts reaction of thiophene with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)$ acetate (1) gave ethyl ${\alpha}-methylthio-2-thiopheneacetate$ (3). Ethyl ${\alpha}-methyl-2-thiopheneacetate$ (5) was prepared by treatment of (3) with NaH and MeI, followed by desulfurization with zinc dust-acetic acid of the resultant ethyl ${\alpha}-methyl-{\alpha}-methylthio-2-thiopheneacetate$ (4). Tiaprofenic acid (7) could be easily synthesized by benzoylation of (5) and hydrolysis of the resultant ethyl $5-benzoyl-{\alpha}-methyl-2-thiopheneacetate$ (6).

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2303-2312
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• 2018

Pretreatment process of silica-coated PET fabrics, a major low-grade PET waste, was developed using the reaction with NaOH solution. By destroying the structure of silica coating layer, impurities such as silica and pigment dyes could be removed. The removal of impurity was confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The pretreated PET fabric samples were used for depolymerization into its monomer, bis(2-hydroxylethyl) terephthalate (BHET), by glycolysis with ethylene glycol (EG), and zinc acetate (ZnAc) catalyst. The quality of BHET was confirmed by DSC, TGA, HPLC and NMR analyses. The highest BHET yield of 89.23% was obtained from pretreated PET fabrics, while glycolysis with raw PET fabric yielded 85.43%. The BHET yield from untreated silica-coated PET fabrics was 60.39%. The pretreatment process enhances the monomer yield by the removal of impurity and also improves the quality of the monomer.

• Bulletin of the Korean Chemical Society
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• 제16권7호
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• pp.672-674
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• 1995

• 한국재료학회지
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• 제27권10호
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• pp.530-533
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• 2017

ZnO micro/nanocrystals with different morphologies were synthesized by thermal evaporation of various zinc source materials in an air atmosphere. Zinc acetate, zinc carbonate and zinc iodide were used as the source materials. No catalysts or substrates were used in the synthesis of the ZnO crystals. The scanning electron microscope(SEM) image showed that the morphology of ZnO crystals was strongly dependent on the source materials, which suggests that source material is one of the key factors in controlling the morphology of the obtained ZnO crystals. Tetrapods, nanogranular shaped crystals, spherical particles and crayon-shaped crystals were obtained using different source materials. The X-ray diffraction(XRD) pattern revealed that the all the ZnO crystals had hexagonal wurtzite crystalline structures. An ultraviolet emission was observed in the cathodoluminescence spectrum of the ZnO crystals prepared via thermal evaporation of Zn powder. However, a strong green emission centered at around 500 nm was observed in the cathodoluminescence spectra of the ZnO crystals prepared using zinc salts as the source materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.193-196
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• 1999

Organic electroluminescent devices have attracted a great deal of attention due to thier potential application to full-color flat-panel displays. The 8-hydroxyquinollne Zinc(Znq$_2$) were synthesized successfully from zinc chloride(ZnCl$_2$) and zinc acetate(Zn(C$_2$H$_3$O$_3$)$_2$) as green omitting material. A double-layer ELD consist of an emitting layer of B-hydroxyquinoline Zinc(Znq$_2$) and a hole-transport layer of tai-phenylene diamine(TPD) derivatives sandwiched between an Aluminium(Al) and Indium-Tin-Oxide(ITO) electrodes omitted green light resulting from Znq$_2$. The electroluminescent devices (ELD) exhibited a maximum luminance of 1000cd/$\textrm{cm}^2$ at a driving voltage of 8V and a driving current density of 0.4mA/$\textrm{cm}^2$.

• Asian-Australasian Journal of Animal Sciences
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• 제21권9호
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• pp.1348-1354
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• 2008

Two inorganic (zinc sulfate and zinc oxide) and three organic (zinc acetate, zinc-methionine, and zinc-lysine) zinc sources were evaluated for their effects on the performance and carcass characteristics of broiler chicks. The birds were randomly assigned to one control (non-supplemented) and 15 treatment (supplemented) groups consisting of four replicates of 10 chicks each in a $5{\times}3$ factorial arrangement of treatments (five zinc sources and three supplemental zinc levels). Birds were kept in floor pens in a temperature-controlled room from 1 to 42 d of age and fed a non-supplemented basal diet (control) or the basal diet supplemented with 40, 80 or 120 mg/kg of Zn as mentioned sources. Dietary zinc source had considerable effect on feed intake in all experimental periods. Increasing Zn level from 80 to 120 mg/kg decreased the average feed intake in the growth stage (p<0.01) and also in the entire experimental period (p<0.001). Similarly, the average daily gain during the entire trial period was affected by the type of Zn source (p<0.001) and supplemental level (p<0.01). One degree of freedom contrast comparisons showed that the inclusion of organic zinc sources into the diets caused significant increases in feed intake and body gain when compared with inorganic counterparts. Except in wk 1, dietary supplementation with organic sources improved (p<0.05) feed conversion ratio; FCR values were not affected by dietary Zn source or supplementation level. Breast meat yield increased with supplemental levels of organic Zn sources; however, other carcass parameters were not affected by dietary Zn source. On the other hand, organic versus inorganic zinc supplementation caused a significant increase in liver, breast and carcass weight percentages. The present findings suggest that supplemental levels of organic Zn compounds had beneficial effects on broiler performance, and Zn requirements can be reduced using these feed supplements in poultry rations.

• 약학회지
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• 제35권2호
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• pp.119-122
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• 1991

A convenient method for the synthesis of ibuproxam, which is a non steroidal antiinflammatory agent, is reported. Friedel-Crafts reaction of isobutylbenzene with ethyl $\alpha$-chloro-$\alpha$-(methylthio)acetate (3) gives ethyl $\alpha$-methylthio-(p-isobutylpheny) acetate (4). Ethyl 2-methylthio-2-(4-isobutylphenyl) propionate (5) is obtained from methylation of the compound (4) with NaH and Mel. lbuproxam (7) is easily synthesized by reductive desulfurization of the compound (5) with zinc dust-acetic acid or Raney nickel, followed by treatment of the resultant ethyl 2-(4-isobutyl-pheny) propionate (6) with H$_{2}$NOH-HCI.

• 약학회지
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• 제41권4호
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• pp.480-483
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• 1997

The efficient synthesis of p-(acetylamino)phenylacetic acid(7), a antirheumatic agent, is reported. Methyl phenylacetate(3) was prepared from Friedel- Crafts reaction of benzene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate(1) followed by reductive desulfurization with zinc dust in acetic acid. Compound(7) was obtained from 3 by a sequence of nitration, reduction, N-acylation, and hydrolysis.